1. Field of the Invention
The present invention generally relates to a key driving apparatus and a keyboard musical instrument.
Priority is claimed on Japanese Patent Application No. 2006-082351, filed Mar. 24, 2006, the content of which is incorporated herein by reference.
2. Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
Conventional keyboard musical instruments such as electronic keyboards and acoustic pianos include a key driving apparatus for driving each key independently. In the keyboard musical instruments, the key driving apparatus drives each key in accordance with a set of performance information. The set of performance information includes a series of musical tones forms a music.
Japanese Unexamined Patent Application, First Publication, No. 59-37594 discloses a conventional key driving apparatus that uses a solenoid as an actuator, to which a driving voltage or a driving signal is supplied so as to drive each key.
Japanese Unexamined Patent Application, First Publication, No. 2004-294769 discloses a conventional key driving apparatus that uses a combination of a stepping motor and a gear mechanism as an actuator, to which a driving voltage or a driving signal is supplied so as to drive each key.
Japanese Unexamined Patent Application, First Publication No. 6-222752 discloses a conventional key driving apparatus that uses a shape memory alloy as an actuator, to which a driving voltage or a driving signal is supplied so as to drive each key.
These conventional key driving apparatuses use the solenoid, the stepping motor in combination with the gear mechanism as the actuators. These conventional key driving apparatuses have relatively large sizes and heavy weights which deteriorate portability of a keyboard musical instrument. Namely, these conventional key driving apparatuses are not suitable for application to portable keyboard musical instruments such as electronic keyboards.
The conventional key driving apparatuses use the actuators that need a large power consumption to obtain a sufficient driving force in an initial phase stage of the key driving operation. These conventional key driving apparatuses are not suitable for the electronic keyboard using a battery.
The conventional key driving apparatus using the shape memory alloy as the actuator can be reduced in size and weight. Deformation of a shape memory alloy is caused by heating or cooling the same. The conventional key driving apparatus using the shape memory alloy can not exhibit large driving force and high driving speed.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved key driving apparatus and a keyboard musical instrument. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.